蜜月期現象與長期報酬關聯性之研究

A Study on the Association between the Honeymoon Effect and Long-term Return

本研究探討新上市時「蜜月期」此一短期股價績效與上市後之長期股價績效之關聯。文獻對「蜜月期」現象，計有承銷商與公司刻意低估承銷價與市場過度樂觀之期初熱潮兩種解釋。而本研究推論，體質較佳之新上市公司，因得藉由較透明之資訊揭露緩和投資人之資訊不足，故承銷價低估或股價錯誤高估之程度均應較小，故體質較佳之新上市公司初期股價雖較無明顯飆漲，但上市後其長期股價報酬將優於體質較差之新上市公司。本研究選取民國78 年至民國97 年間上市之公司為研究樣本，檢視其「蜜月期」現象之有無，與上市後一、二、三、四及五年之累積異常股價報酬之關聯性。實證結果顯示，存在「蜜月期」現象之新上市公司，其上市後之長期股價報酬較差。

We study that the stock price soaring of IPO company, which is so-calledhoneymoon effect, is inversely correlated with the long-term stock return of thatcompany. Researches find that the honeymoon effect is due to the underpricing ofthe IPO issuing, or the market overpricing under the initial fad. We think that thestock of a company with good performance, signaling with more sufficientinformation disclosures, will be priced correctly during the IPO issuing. Our resultsempirically support that the IPO company without honeymoon effect, however, willhas superior long-term stock return.